Circuit breaker



May 31, 1932- H. MILLIKEN CIRCUIT BREAKER 3 Sheets-Sheet l Filed Aug. 26, 1929 El 122 12324125'86 12v 5 \1 1 I 5) u 5| m B a 0 0/ J J J m w w m .0. E E E E R W W Z WW 7 T T B m w w m m R 3 m. 9% w m m flm 1M 1 m M a 9* a J 9 a May 31, 1932. 1;, MI EN 1,861,129

CIRCUIT BREAKER Filed Au 26, 1929 s Sheets-Sheet 2 Patented May 31, 1932 1,861,129

UNITED STATES PATENT OFFICE numrmanys MILLIKEN, OF MONTREAL, QUEBEC, CANADA.

CIRCUIT BREAKER Application filed August 26, 1929. Serial No. 388,566.

This invention has relation to circuit thereby introducingalarge quantity of resistbreake'rs adapted for use on high power cirance with a small motion within a short time, cuits, and the object of the invention is to thus minimizing heating and the required avoid the formation of destructive arcs when size of the resistors. As will be observed, the circuit is opened, as more fully hereinthe resistors are arranged in a plurality of 55 after set forth. rows connected? together electrically at their In the drawings annexed alternate ends by conductors b, the row at one Fig. 1 is a diagram showing the circuit arend being connected by conductor to the rangement; main contact 2, and the row at the other end Fig. 2 is a horizontal sectional view of the series being connected by conductor 0 through the circuit breaker on the line 22 (2 to the usual shunt-horn 8, with which the of Fig. 3; blade 3 maintains contact for a short distance ig. 3 is a vertical sectional view through after it leaves the jaws 2.

the apparatus shown in Fig. 2; Qonductor-bars are supported on insu- Fig. 4 is a detail sectional view showing a latmg arms 6 which insulate each conductorc5 slight modification. bar separately. When the conductors 5 have Fig. 5 is a detail sectional view showing the reached their extreme open position, all of formation of th blast hann ls. I the resistors are in circuit in the series, which Fig. 6 is a detail diagrammatic view of one reduces the current to a small value, which of th bank of r istor small current is broken by the separation of 7 Fig. 7 is a perspective view showing one the blade 3 from the usual horn 8, no air possible arrangement ofmy device. blast being required to break any are that The invention will be best understood by might be formed between 3 and 8 by this first describing the diagram, Fig. 1. In this Small current. As shown in Fig. 1, resistors diagram, the current enters by lead 1, the R are connected alternately between adja- 7 usual main blade 3 and out by lead 4. When cent resistors B so as to maintain a closed the main blade 3 is opened to the dotted-line circuit after all of the resistors are inserted, position, current cannot pass from contact 2 these resistors R havingRa much higher reto blade 3, and hence it flows through a shunt s an e th n re istors Resistor R path consisting of a supplemental or shuntmight be omitted entirely, leaving the cirso contact-horn 8 and a. series of resistors herecuit 0 en at these points, but it is better to inafter described. At theinstant that blade3 pr vi e a very high resistance R so as to breaks contact with 2, all the resistors are equalize the potential and stress on the inshort circuited by conductor-bars 5, assumsulation of the structure which carries the 5 ing that these bars are in their xtr m leftresistors. Resistor R has the least resistance 'hand position and that, therefore, no arc is and R" the highest resistance, intermediate drawn between 2 and 3 whenthey se arate. resistors having intermediate values of re- Immediately after the separation of 2 om 3, sistance. Resistor R has the highest current 3 trips a mechanism (hereinafter described) capacity and R" the least current capacity, 40 which starts all the conductor-bars 5 moving intermediate resistors having intermediate toward the right, to thereby introduce resistcurrent capacities. The current is reduced ors R, R, R, etc. successively. step by step by the introduction of each re- Just before blade 2 opens, an air blast is sistoy. The resistances are so proportioned opened so as to play across all the contacts that the product of current times resistance .5 19 of the resistors. Hence the separation of increases as the current decreases, to thereby conductors 5 from the contact points of these equalize the arcing at the successive contact resistors takes place within a strong blast of points. air, which blows away the ionized atmosphere One advantage of this construction is that and the hot air and thus minimizes the arca very large current resulting from a short 50 ing All of the conductors 5 move together, circult on the system is quickly reduced to 1.0

a small current before the circuit is opened, thereby avoiding the damaging effect of drawing an are carrying the entire shortcircuit current. Another advantage is that the reduction of current before breaking the circuit avoids the objectionable voltage surges which are well known to result from the usual methods of switching large curand the results will be the same as if ten sections were tested on- 66,000 volts. The capacity of ten sections might be 1,000,000 kilo-volt-amperes. It is a very difiicult matter to arrange for such a large supply of power for tests, but one section will require only one-tenth, i. e., 100,000 k. v. a., supply for testing.

The conductor-bars 5 are preferably made in tapered form and they are atfixed to a rockshaft 9 by means of. the aforesaid insulating arms 6. A crank 12 and spring 13 impart quick motion to the set of bars 5 when toggle 10'is opened inwardly by the blade 3 striking a finger 14: on one arm of the toggle. The air blast shown by the arrows enters opening 15 to passage 16 and out through orifices 17 and arc-chutes 18, these passages being formed in a block or mass of suitable insulating material 20. Contactbars 19 embedded in the sides of the arcchutes 18 make contact with bars 5 and are connected to the resistors R, etc. Desirably, the bars 19 are inclined with respect to the spring contact 21 carried by each of the bars 5, so as to assist in causing the arcs to be blown away from parts 21 and 19 when they separate. Also, desirably, the bars 19 are made straight so that they can be pulled out and renewed readily, if burned.

Only half of the bars 19 are shown in Fig. 3; the other bars 19 are at the near side of the orifice 17 and blast-chutes 18. A spring 7 assists in imparting a quick start to the set of contact-bars 5. The air blast also assists in accelerating the conductors 5 by blowing against the ends thereof as these bars leave the chutes 18. It is very desirable to bring into the shunt circuit all of the resistors in the shortest possible time.

In closing the main contacts, blade 3 strikes arm 11 of the toggle and closes the toggle and thus throws the contact-bars 5 back into the arc-chutes against the action of springs 7 and 13. A lid 22 secured to wall 20 by hinges 23 protects the interior from weather. The air blast opens lid 22 against the action of a spring on hinge 23,

to exclude the weather, and 26 is a housing for the resistors. The body of the apparatus such, for instance, as asbestos board. The contacts 21, 'on each of the bars 5, are of spring metal and they are long enough to span at least two of the contacts 17 so as to avoid opening the circuit before'all the reis made of arc-resisting, insulating material,

employed for this purpose. It will be understood also that this air blast is turned 'on an instant before the movable resistorcontacts 21 leave the first set of stationary resistor-contacts 19 and is continued until these movable resistor-contacts 21 pass oif the. last contact-bars 19. In Fig. 7 I have I "shown one convenient way of actuating the movable parts of my apparatus; I do this by connecting a cylinder 28 to the air blast pipe 29 and by means of a piston 30 in said cylinder 28, which is actuated when the air blast is turned on, I throw 0 en the main blade 3, which blade, as hereto ore set forth,

actuates a toggle device which in turn with draws the bars 5.

As shown in Fig. 5, it is desirable that the arc-chutes 18 shall be made to widen toward their exit-ends for the purpose of reducing nor as if contact 21 made contact with all [the bars 19. The advantage of this construction is thatthe resistors are inserted much more quickly than is possible by a mechanical motion of the conductor-bars 5, thereby rei-fducing the heating of the resistors or increasing the interrupting capacity of the circuit breaker. It will be understood that those of the bars 19 shown in Fig. 4 which do not make actual direct contact with the horn 5 are nevertheless contacts within the mean ing of the claims.

' of circuit breaker has not met with much switch.

favor, principally because accidents have occurred whereby the resistance or reactance was left in the circuit continuously, becoming hot and igniting the oil, causing serious fires. My construction avoids the possibility of having the resistor in circuit continuously and, also, I avoid the use of oil or other inflammable substance. My resistors are desirably made of aphite and clay products, so'as to be incom ustible.

Instead of air alone for the blast, the conductivity of the arc per unit volume may be 'reducedby injecting into the air blast gases or finelydivided material, either solids or liquids, servingto cool the are or otherwise reduce its conductivity. Also compressed carbon dioxide, either in liquid or gaseous form, may be used for the purpose of providing a non-oxidizing atmosphere to extinguish flame due to burning of metal vapor; any other non-oxidizing material may be used, such as carbon tetrachloride. i

What I claim asnew is:

1. In a circuit breaker, a main circuit means including a main switch, a shunt circuit associated therewith and including a plurality of rows of resistors, each resistor having astationary-contact, an insulating structure having open-ended air channels, one for each row of said stationary contacts, the contacts being located in the channels, the inlet ends of said channels being connected to an air-blast conduit a conductor-bar adapted to pass into each of said channels and carrying a movable resistor-contact positioned to cooperate with said stationarycontacts as the conductor-bar is withdrawn from the channel to thereby successively cut in the resistors in the shunt circuit, and means whereby all saidconductor-bars are quickly withdrawn from said channels in the direction of the air-blast upon the opening of the main switch, whereby a multiplicity of resistors are brought into action almost instans taneously after the opening of said main 2. The structure recited in claim 1, the channels in which stationary-contacts are arranged being tapered outward so that as the conductor-bars move out of the channels, the movable contact carried by each conductor-bar will have actual contact with only the contact stationary at the inner end of its channel. a

3. In a device of: the class described, an

' electric circuit embodying a plurality of rows of resistors, each resistor having a stationary contact, an insulating structure having open ended air channels, one for each row of said stationary contacts, the inlet ends of said channels being connected'to an air-blast conduit so that air blasts may be sent through said conduits simultaneously, a conductorbar adapted to pass into each of said channels and carrying a movable resistor-contact positioned to co -operate with said stationary contacts as the conductor-bar is withdrawn from its channel to thereby successivelyx in the resistors, and mechanical devices w ereby all said conductor-bars are quickly withdrawn from said channels in the direction of the air blasts, whereby a multiplicity of resistors are brought into action almost simultaneously, the speed being augmented by said air blasts.

4. In a device of the class described, an electric circuit'including a plurality of rows of resistors, each resistor having a stationary contact, a plurality of movable resistor-contacts adapted when moved to successively cut in said resistors, means whereby said movable resistor-contacts are simultaneously moved to cut in said resistors, and additional high-resistance potential-equaliZing-resistors in position to be cut into said circuit by said movable resistor-contacts after the resistors of signature.

HUMPHREYS MILLIKEN. 

